Attentional requirements of walking according to the gait phase and onset of auditory stimuli.

A dual-task paradigm was used to examine the influence of an attention demanding cognitive task on each phase of gait. Twenty-three participants (aged 18-27) walked on a treadmill at a 20% increase of their self-selected speed, either alone or while performing a cognitive task. Muscle activity was measured with electromyography (iEMG) for eight muscles of the dominant leg. The cognitive task consisted of subtracting one (EASY) or seven (HARD) from orally presented numbers. Reaction time (RT) and accuracy were recorded. iEMG events were selected according to stimulus onset (0-150 ms, 150-300 ms and 300-450 ms) prior to phases of gait (double-leg stance, single-leg stance and swing). There was a decrease in iEMG amplitude of fibularis longus (p=.013) and a trend in the same direction for vastus lateralis (p=.065) while walking and performing the cognitive task. When stimulus onset was considered, iEMG of medial gastrocnemius (p=.021) and lateral gastrocnemius (p=.004) were reduced during single-leg stance, when stimuli occurred between 300 and 450 ms prior to this phase. Cognitive performance was affected by task difficulty (RT, accuracy) and by dual-task load (RT). Dual-task costs were observed in both the motor and the cognitive tasks, suggesting that walking requires attention. There was a specific moment (300 ms after stimulus onset) during single-leg stance when dual-task costs were most pronounced, corroborating supraspinal involvement in the control of normal walking. Time-based approaches should be considered when analyzing attentional demands of a dynamic task such as gait.

[1]  M. Woollacott,et al.  Attention and the control of posture and gait: a review of an emerging area of research. , 2002, Gait & posture.

[2]  Marjorie H. Woollacott,et al.  Motor Control: Theory and Practical Applications , 1995 .

[3]  O. Spreen,et al.  A Compendium of Neuropsychological Tests: Administration, Norms, and Commentary , 1991 .

[4]  D. Winter Foot trajectory in human gait: a precise and multifactorial motor control task. , 1992, Physical therapy.

[5]  M. Gossman,et al.  Balance performance among noninstitutionalized elderly women. , 1989, Physical therapy.

[6]  F. Irani,et al.  Functional Near Infrared Spectroscopy (fNIRS): An Emerging Neuroimaging Technology with Important Applications for the Study of Brain Disorders , 2007, The Clinical neuropsychologist.

[7]  Bruce Abernethy,et al.  The attentional demands of preferred and non-preferred gait patterns. , 2002, Gait & posture.

[8]  S M Lephart,et al.  Muscle preactivity of anterior cruciate ligament-deficient and -reconstructed females during functional activities. , 1999, Journal of athletic training.

[9]  J. Duysens,et al.  Abeta fibers mediate cutaneous reflexes during human walking. , 2000, Journal of neurophysiology.

[10]  J. Hertel,et al.  Lower-Extremity Muscle Activation during the Star Excursion Balance Tests , 2001 .

[11]  Julien Barra,et al.  Increasing cognitive load with increasing balance challenge: recipe for catastrophe , 2006, Experimental Brain Research.

[12]  L. Bouyer,et al.  Visual-vestibular influences on locomotor adjustments for stepping over an obstacle , 2007, Experimental Brain Research.

[13]  Christopher Kirtley,et al.  Clinical Gait Analysis: Theory and Practice , 2006 .

[14]  M. Morris,et al.  Dual task interference during gait in people with Parkinson disease: effects of motor versus cognitive secondary tasks. , 2002, Physical therapy.

[15]  J. Stroop Studies of interference in serial verbal reactions. , 1992 .

[16]  K Kurosawa Effects of various walking speeds on probe reaction time during treadmill walking. , 1994, Perceptual and motor skills.

[17]  Luigi Baratto,et al.  A new look at posturographic analysis in the clinical context: sway-density versus other parameterization techniques. , 2002, Motor control.

[18]  Brian E. Maki,et al.  The time course of attention shifts following perturbation of upright stance , 2002, Experimental Brain Research.

[19]  C. Bard,et al.  Attentional demands for static and dynamic equilibrium , 2004, Experimental Brain Research.

[20]  P. Baltes,et al.  Walking While Memorizing: Age-Related Differences in Compensatory Behavior , 2001, Psychological science.

[21]  Bradford J. McFadyen,et al.  Vestibular contributions across the execution of a voluntary forward step , 2002, Experimental Brain Research.

[22]  Li-Shan Chou,et al.  The effect of divided attention on gait stability following concussion. , 2005, Clinical biomechanics.

[23]  J. Duysens,et al.  A b Fibers Mediate Cutaneous Reflexes During Human Walking , 2000 .

[24]  H. Buschke,et al.  Walking while talking: effect of task prioritization in the elderly. , 2007, Archives of physical medicine and rehabilitation.

[25]  Martin Wiesmann,et al.  Imaging human supraspinal locomotor centers in brainstem and cerebellum , 2008, NeuroImage.

[26]  P. Goldie,et al.  Gait after stroke: initial deficit and changes in temporal patterns for each gait phase. , 2001, Archives of physical medicine and rehabilitation.

[27]  H. Fukuyama,et al.  Brain functional activity during gait in normal subjects: a SPECT study , 1997, Neuroscience Letters.

[28]  S J Day,et al.  Experimental simulation of cat electromyogram: evidence for algebraic summation of motor-unit action-potential trains. , 2001, Journal of neurophysiology.

[29]  W. Gage,et al.  Is the prioritization of postural control altered in conditions of postural threat in younger and older adults? , 2002, The journals of gerontology. Series A, Biological sciences and medical sciences.

[30]  Alan C. Evans,et al.  Motor Learning Produces Parallel Dynamic Functional Changes during the Execution and Imagination of Sequential Foot Movements , 2002, NeuroImage.

[31]  R. Stein,et al.  Factors that determine the magnitude and time course of human H- reflexes in locomotion , 1991, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[32]  Michael W. Whittle,et al.  Gait Analysis: An Introduction , 1986 .

[33]  J. T. Inglis,et al.  When is vestibular information important during walking? , 2004, Journal of neurophysiology.

[34]  J. Hertel,et al.  Intratester and Intertester Reliability during the Star Excursion Balance Tests , 2000 .

[35]  B. Bussel,et al.  Evidence for Cognitive Processes Involved in the Control of Steady State of Walking in Healthy Subjects and after Cerebral Damage , 2005, Neurorehabilitation and neural repair.

[36]  P Haggard,et al.  Interference between gait and cognitive tasks in a rehabilitating neurological population , 2000, Journal of neurology, neurosurgery, and psychiatry.

[37]  S. Brauer,et al.  Does the type of concurrent task affect preferred and cued gait in people with Parkinson's disease? , 2005, The Australian journal of physiotherapy.

[38]  Jean Pailhous,et al.  Intentional on-line adaptation of stride length in human walking , 1999, Experimental Brain Research.

[39]  M. Herrmann,et al.  Common brain regions underlying different arithmetic operations as revealed by conjunct fMRI–BOLD activation , 2007, Brain Research.

[40]  Ichiro Miyai,et al.  Prefrontal and premotor cortices are involved in adapting walking and running speed on the treadmill: an optical imaging study , 2004, NeuroImage.

[41]  E. Zehr,et al.  Task-specific modulation of cutaneous reflexes expressed at functionally relevant gait cycle phases during level and incline walking and stair climbing , 2006, Experimental Brain Research.

[42]  Olivier Daniel,et al.  Human treadmill walking needs attention , 2006, Journal of NeuroEngineering and Rehabilitation.

[43]  M. Herrero,et al.  Functional anatomy of thalamus and basal ganglia , 2002, Child’s Nervous System.

[44]  Stephen J. Boies,et al.  Components of attention. , 1971 .

[45]  C. Capaday The special nature of human walking and its neural control , 2002, Trends in Neurosciences.

[46]  Virginia B Penhune,et al.  Effects of balance status and age on muscle activation while walking under divided attention. , 2007, The journals of gerontology. Series B, Psychological sciences and social sciences.

[47]  Itshak Melzer,et al.  The Effect of a Cognitive Task on Voluntary Step Execution in Healthy Elderly and Young Individuals , 2004, Journal of the American Geriatrics Society.

[48]  V. Dietz,et al.  Single joint perturbation during gait: neuronal control of movement trajectory , 2004, Experimental Brain Research.

[49]  M. Woollacott,et al.  Cognitive influence on postural stability: a neuromuscular analysis in young and older adults. , 2000, The journals of gerontology. Series A, Biological sciences and medical sciences.

[50]  W Poewe,et al.  Influence of Concurrent Tasks on Gait: A Dual-Task Approach , 1995, Perceptual and motor skills.

[51]  J. Friedman Gait in the elderly. , 2008, Medicine and health, Rhode Island.

[52]  Li-Shan Chou,et al.  Cognitive task effects on gait stability following concussion , 2006, Experimental Brain Research.

[53]  P. Gribble The Star Excursion Balance Test as a Measurement Tool , 2003 .

[54]  H. Pashler Dual-task interference in simple tasks: data and theory. , 1994, Psychological bulletin.

[55]  Roger P. Woods,et al.  Ankle dorsiflexion as an fMRI paradigm to assay motor control for walking during rehabilitation , 2004, NeuroImage.

[56]  I. Melzer,et al.  Age-Related Changes of Postural Control: Effect of Cognitive Tasks , 2001, Gerontology.

[57]  John V. Basmajian,et al.  Electrode placement in EMG biofeedback , 1980 .

[58]  Jay Hertel,et al.  Considerations for Normalizing Measures of the Star Excursion Balance Test , 2003 .

[59]  D. Armstrong The supraspinal control of mammalian locomotion. , 1988, The Journal of physiology.

[60]  M. MacKay-Lyons Central pattern generation of locomotion: a review of the evidence. , 2002, Physical therapy.

[61]  F. Horak Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls? , 2006, Age and ageing.

[62]  G Borg,et al.  Ratings of Perceived Exertion and Heart Rates During Short-Term Cycle Exercise and Their Use in a New Cycling Strength Test* , 1982, International journal of sports medicine.

[63]  Jeffrey M. Hausdorff,et al.  Walking is more like catching than tapping: gait in the elderly as a complex cognitive task , 2005, Experimental Brain Research.

[64]  Shu-Chen Li,et al.  Dual-tasking postural control: Aging and the effects of cognitive demand in conjunction with focus of attention , 2006, Brain Research Bulletin.